LARGE BANDWIDTH BICMOS OPERATIONAL-AMPLIFIERS FOR SC VIDEO APPLICATIONS

A single-ended and a fully differential broadband BiCMOS operational a mplifier for switched-capacitor video applications are presented. The amplifiers feature a folded cascode gain stage with a current source a s output load. For the single-ended amplifier the current mirroring is accomplished with a modified bipolar Wilson current mirror at the out put of the differential pair. Symbolic expressions for the transfer fu nctions for both amplifiers are derived. The amplifiers are integrated in an analog 1 mu m BiCMOS process with an active die area of 0.72 mm (2) and 0.96 mm(2) for the single-ended and the fully differential amp lifier, respectively. For both amplifiers a DC-gain of 68 dB and a uni ty gain frequency greater than 250 MHz was measured for a power supply voltage of 5 V.